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Group set to demonstrate MPEG rival

Pulsent Corp. of Milpitas, CA is set to demonstrate its new coding algorithm at next month's National Association of Broadcasters' convention, where it will join other groups such as Apple, DemoGraFX, DivX, iVast, Microsoft, On2, and RealNetworks. Pulsent's digital video compression was designed as an object-based algorithm, in contrast to MPEG which, although MPEG-4 uses object-based coding, has its roots in block-based technology.

"MPEG has done a good job squeezing more out of the existing technology, but we feel that block-based video coding has reached its limits." Rather than rely on block-based motion compensation to predict the next frame, Pulsent's scheme uses an object in one frame to model itself in subsequent frames.

But object-based coding has its detractors. "Not all pictures can be segmented into objects," said Didier LeGall, vice president of home media products at LSI Logic Corp. (Milpitas). "To do object-based video coding for a particular class of a picture is possible, but to do it for generic materials — sports, news, movies, science programs and the like — is very difficult." LeGall professed to have more "skepticism than faith" that such schemes will prove practical.

The major market of new coding algorithms will be the broadcast industry, where better compression techniques would allow more content to be transferred over networks with finite bandwidth. Supporters of MPEG contend that there is already a large infrastructure designed for MPEG transmissions, but Pulsent says its technology is compatible with existing transport stream protocols. Pulsent says they can re-encode a 3Mbit/s MPEG-2 stream to about a 1.5Mbit/s Pulsent stream, although questions remain about how great an effect that additional encoding will have on video quality.